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[From  the  BuiraTii/o&-rHff  Torrey  Botanical  Club  45:  259-277,  6 Au  1918.  | 

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The  strand  flora  of  the  Hawaiian  Archipelago — I.  Geographical  re- 

lations, origin,  and  composition 

/ 

Vaughan  MacCaughey 

GEOGRAPHICAL  RELATIONS 

For  a long  time  botanists  have  manifested  particular  interest 
in  the  strand  vegetation  of  various  countries.  The  floras  of  many 
continental  and  insular  strands  have  alike  * yielded  significant 
material.  There  is,  however,  absolutely  no  comprehensive  ac- 
count of  the  Hawaiian  littoral.  Fragmentary  and  uncoordi- 
nated notes  concerning  various  Hawaiian  strand  plants  are  given 
by  Hillebrand,  Wawra,  Gray,  Chamisso,  Heller,  Mann,  Schauins- 
land,  Forbes,  and  other  botanists,  who  at  various  times  during 
the  past  century  have  studied  the  Hawaiian  flora.  In  the  works 
of  none  of  these  investigators  is  the  littoral  flora  given  any  special 
prominence  or  consideration.  This  is  somewhat  surprising,  as 
much  of  the  Hawaiian  coast  line  is  readily  accessible  by  boat  or 
trail,  whereas  the  montane  districts  present  innumerable  diffi- 
culties to  the  explorer  and  collector. 

Guppy  ( ’06),*  in  connection  with  his  suggestive  studies  of  plant 
dispersal  in  the  Pacific,  visited  the  Hawaiian  Archipelago  and 
studied  the  strand  flora  with  reference  to  the  general  problems  of 
evolution  and  distribution.  Frequent  references  are  made  to 
Guppy’s  work  in  the  present  paper.  His  brilliant  theories  will 
undoubtedly  require  more  or  less  revision  as  data  concerning  the 
Pacific  flora  become  more  comprehensive  and  standardized. 

* The  literature  cited  will  be  listed  in  the  second  paper  of  this  series. 

259 


260 


MacCaughey:  The  strand  flora 


The  unique  position  of  the  Hawaiian  Islands,  as  the  most 
northern  group  of  the  great  Polynesian  island  series,  and  as  a 
region  of  extreme  isolation,  gives  particular  significance  to 
its  strand  flora.  The  absences  from  this  flora  are  as  important 
criteria  as  are  the  species  actually  present,  and  in  many  ways 
contribute  as  effectively  to  our  knowledge  of  the  origin  and  history 
of  Hawaii’s  strand  flora. 

The  attempt  is  here  made  to  present  a salient  account  of  the 
Hawaiian  littoral  flora,  both  from  the  standpoint  of  content  and 
dispersal,  and  also  from  the  ecological  viewpoint.  In  the  latter 
phases  of  the  subject  the  author  has  been  particularly  interested. 
During  a residence  of  nine  years  in  the  islands  he  has  made  hun- 
dreds of  excursions  along  Hawaiian  strands,  including  the  prin- 
cipal islands  of  the  archipelago.  The  present  papers  incorporate 
the  important  data  of  these  field  studies. 

A noteworthy  feature  of  the  littoral  floras  of  the  tropical 
Pacific  islands  is  their  remarkable  similarity . As  Hedley  (’15) 
expresses  it:  “The  same  species  are  repeated  from  atoll  to 
atoll  over  enormous  distances  across  the  Pacific  Ocean.  The 
identity  of  the  vegetation  possessed  by  tiny  islets  separated  by 
thousands  of  miles  of  deepest  ocean  is  very  striking,  since  para- 
doxically they  present  a greater  continuity  of  life  range  than  any 
continent  can  show."  Many  of  the  more  common  Hawaiian  lit- 
toral plants  occur  on  practically  all  the  islands  of  the  archipelago, 
along  an  axis  of  nearly  two  thousand  miles,  whereas  the  montane 
species  are  highly  localized. 

Just  as  the  interior  mountainous  districts  of  a high  Pacific 
island  contain  the  majority  of  the  endemic  species,  so  the  strand 
regions  are  characterized  by  a majority  of  the  cosmopolitan  or 
wide-ranging  species.  Tansley  and  Fritsch  (’05)  find  two  main 
causes  for  “the  striking  uniformity  of  strand  plants  through  the 
tropics — first,  the  great  similarity  of  life  conditions  prevailing  on 
tropical  coasts,  and  secondly,  tropical  strand  plants  are  mostly 
adapted  for  distribution  by  ocean  currents.”  These  factors  will 
be  considered  in  detail  in  later  sections  of  this  paper. 

As  will  be  shown  later,  the  Hawaiian  littoral  flora  comprises 
many  species  that  occur  in  other  parts  of  the  Pacific,  and  in  many 
other  parts  of  the  world.  The  mountain  flora,  on  the  contrary, 


of  the  Hawaiian  Archipelago 


261 


is  highly  endemic  and  precinctive,  and  each  island  possesses  an 
array  of  peculiar  forms.  The  Hawaiian  Islands  therefore  obey 
the  general  law  of  the  cosmopolitanism  of  littoral  constituents. 

The  geographic  situation  of  the  Hawaiian  Islands  is  unique, 
and  has  a very  important  bearing  upon  the  character  of  the  strand 
flora.  There  is  no  other  land  area  of  equal  magnitude  on  the 
earth  that  is  so  far  removed  from  continental  land  areas.  The 
Hawaiian  Islands  are  the  most  isolated  islands,  of  their  size,  in 
the  world,  and  their  flora  strikingly  and  faithfully  registers  this 
profound  and  prolonged  isolation.  An  examination  of  a map 
of  the  North  Pacific  Ocean  will  show  the  nature  of  this  isolation. 
Using  the  island  of  Oahu,  which  is  situated  in  the  eastern  part  of 
the  archipelago,  as  a base  point,  the  distances  to  adjacent  land- 
masses,  in  terms  of  nautical  miles,  to  ports  specified,  are  as  follows: 


San  Francisco 

2,100 

Fiji 

2,700 

San  Diego 

2,260 

Auckland 

3-.810 

Panama 

Sandakan 

Callao 

5A47 

Hongkong 

Cape  Horn 

6,488 

Yokohama 

3.400 

Tahiti 

2,440 

Vladivostok 

4.721 

Samoa 

Portland 

Unalaska 

2,106 

The  isolation  is  further  emphasized  by  an  examination  of  the 
deep-sea  soundings  in  the  vicinity  of  the  Hawaiian  Islands,  which 
show  that  the  islands  rise  from  abyssal  depths.  The  great  deeps 
of  the  Pacific  Ocean,  which  lie  between  the  Hawaiian  Archipelago 
and  the  continents,  are: 


Name  of  deep 

Position  with  reference 
to  Hawaii 

Maximum  depth  in 
fathoms 

Area  in  square  miles 

Murray 

Due  north 

3.540 

1,033,000 

Supan 

Due  north 

Maurv 

Due  north 

Renard 

Northeast 

Wyman 

Northeast 

Tanner 

Northeast 

Glover 

Northeast 

Agassiz 

Northeast 

Bache 

Northeast 

Moser 

Southeast 

Gray 

Southeast 

Belknap 

South 

3-337 

165,000 

Campbell 

South 

Ammen 

Southwest 

Brooke 

West 

3.429 

282,000 

Bailey 

West 

3.432 

241,000 

Tuscarora 

Northwest 

4.655 

908,000 

262 


MacCaughey:  The  strand  flora 


The  isolation  of  the  Hawaiian  flora  is  reflected  in  the  vegetation 
of  the  littoral  zone  by  the  high  proportion  of  endemic  species, 
32  out  of  a total  of  no,  or  30  per  cent.  Nine  of  these  belong  to 
endemic  genera.  This  is  a remarkable  showing,  since  littoral 
floras,  in  all  parts  of  the  world,  are  usually  comprised  almost  wholly 
of  cosmopolitan  and  non-endemic  constituents. 

South  Pacific  equivalents  of  Hawaii 

In  the  comparisons  which  are  likely  to  be  made  of  the  Hawaiian 
flora  with  those  of  the  South  Pacific  islands  it  is  important  to 
recognize  the  geologic  and  topographic  status  of  the  various 
island  groups.  Guppy  (’06,  p.  14)  makes  the  following  significant 
observationt : 

The  Hawaiian  Islands,  standing  alone  in  the  North  Pacific,  form  a floral  region 
in  themselves,  a region  that  is  the  equivalent  not  of  one  group  in  the  South  Pacific, 
such  as  that  of  Fiji  or  of  Tahiti,  but  of  the  whole  area  comprising  all  the  groups  ex- 
tending from  Fiji  to  the  Paumotu  Archipelago. 

For  the  purposes  of  this  paper  the  islands  and  continental 
coasts  of  the  Pacific  region  may  be  roughly  divided  into  the  fol- 
lowing great  phyto-geographic  provinces,  listed  clockwise  in  and 
around  this  greatest  of  marine  basins.  These  provinces  are  not 
presented  as  of  equal  biological  value  or  range,  but  merely  for 
purposes  of  convenience  in  description. 

1.  Northeastern  Siberia  and  Alaska:  Kamchatka,  Korake,  Tschuktsche, 

Aleutian  Islands,  Alaska,  British  Columbia,  and  coastal  islands. 

2.  Pacific  Coast  of  North  America:  Washington,  Oregon,  California,  and  coastal 

islands. 

3.  Pacific  Coast  of  Mexico  and  Central  America:  Lower  California,  Mexico, 

Guatamala,  Honduras,  Nicaragua,  Costa  Rica,  Panama. 

4.  Pacific  Coast  of  northern  South  America:  Colombia,  Ecuador,  Galapagos 

Islands,  Peru,  Chile,  Juan  Fernandez  Islands. 

5.  Pacific  Coast  of  southern  South  America:  Chile  and  coastal  islands;  Tierra 

del  Fuego. 

6.  Australasia:  Australia,  Tasmania,  New  Zealand,  and  adjacent  islands. 

7.  Malaysia:  Sumatra,  Java,  Borneo,  and  other  Sunda  Islands;  Moluccas,  New 

Guinea,  Philippine  Islands. 

8.  Southeastern  Asia:  China,  Hai-nan,  Indo-China,  Cochin  China,  Cambodja, 

Siam,  Malay  Peninsula. 

9.  Pacific  Coast  of  Central  Asia:  Japan,  Riu-Kiu  Islands,  Formosa,  and  adja- 

cent Asiatic  coasts  and  islands. 

10.  Melanesia:  Bismarck  Archipelago,  Louisiade,  Solomon,  Santa  Cruz,  New 

Hebrides,  and  Loyalty  Islands,  New  Caledonia,  Fiji,  and  intervening  smaller 

groups. 


of  the  Hawaiian  Archipelago 


263 


11.  Mikronesia:  Mariana,  Pelew,  Caroline,  Marshall,  and  Gilbert  Islands,  and 

intervening  islands. 

12.  Polynesia — (a)  Nuclear  Polynesia:  Samoa,  Tonga,  Fiji,  Tokelau,  Ellice  Islands, 

etc. 

(b)  Central  Polynesia:  Cook,  Phoenix,  Tubuai,  Rolcahanga,  Ton- 
garewa,  Manahiki  Islands. 

(c)  Southeast  Polynesia:  Society,  Marquesas,  Taumotu,  Gambier, 
Pitcairn,  Easter,  Ducie  Islands,  etc. 

(d)  Northern  Polynesia:  Hawaiian  Islands. 

(e)  Southern  Polynesia:  New  Zealand  and  Chatham  Islands. 

(f)  Polynesian  Verge:  scattered  islands  between  Polynesia  and 
Melanesia,  such  as  Ticopia. 

Extent  of  the  Hawaiian  littoral 
The  great  length  of  the  archipelago  gives  the  littoral  zone  a 
much  larger  significance  and  extent  than  if  the  archipelago  con- 
sisted of  but  a few  islands  situated  close  together.  The  Hawaiian 
littoral,  ranging  for  nearly  two  thousand  miles,  contrasts  sharply 
with  the  compact  littoral  of  such  groups  as  Samoa,  Tonga,  New 
Caledonia,  Ellice  and  Phoenix.  Other  Pacific  island  groups  which 
are  extended  over  long  axes,  similar  to  Hawaii,  are  the  Aleutian, 
Kurile,  Paumotu,  Marshall,  Caroline,  and  Solomon  Islands. 

The  Hawaiian  strand  occupies  an  island  series  extending  from 
1 8°  54'  to  220  15'  north  latitude,  and  between  1540  50'  and  160°  30' 
of  longitude  west  of  Greenwich.  This  range  should  greatly  in- 
crease the  mathematical  probability  of  plant  dispersal,  and  in 
some  measure  tend  to  neutralize  the  powerful  isolation-factor. 
The  east-and-west  range  of  the  littoral  naturally  results  in  a much 
greater  homogeneity  of  flora  than  would  be  the  case  in  an  archi- 
pelago with  a dominant  north-and-south  axis.  In  this  respect 
the  Hawaiian  Islands  may  be  contrasted  with  such  archipelagofes 
as  the  Philippines,  and  the  Mariana  and  Maidive  groups. 

The  great  variation  in  the  size  and  elevation  of  the  several 
islands  markedly  influences  the  extent  of  the  littoral.  In  general, 
the  low  islands  have  strands  that  extend  further  back  into  the 
interior  than  do  those  of  the  high  islands;  the  small  islands  have  a 
larger  proportion  of  strand,  relative  to  their  total  area,  than  do 
the  large  islands.  The  small,  low  coral  islets  that  predominate 
in  the  western  end  of  the  archipelago  are  littoral  throughout 
practically  all  their  area;  the  large, high  islands  of  Maui  and  Hawaii, 
at  the  eastern  extremity  of  the  archipelago,  have  a narrow  and 
closely  defined  strand. 


264 


MacCaughey:  The  strand  flora 


The  following  islands  have  relatively  wide  strands: 

1.  Ocean,  Kure,  or  Cure  Island:  circular  barrier  atoll,  16  miles  in  circumference; 

area  of  lagoon  about  38  square  miles;  several  low  sand  islets  in  the  lagoon; 
considerable  shrubbery  and  other  low  vegetation  on  the  largest  sand  islet, 
“Green  Island.” 

2.  Midway  or  Brook’s  Island:  circular  barrier  atoll,  18  miles  in  circumference;  area 

of  lagoon  about  40  square  miles;  several  low  sand  islets  in  the  lagoon;  native 
and  introduced  vegetation. 

3.  Pearl  and  Hermes  Reef:  irregular,  oval  barrier  atoll,  42  miles  in  circumference; 

area  of  lagoon  about  80  square  miles;  numerous  low  sand  islets  in  the  lagoon, 
some  with  grasses  and  other  low  vegetation. 

4.  Lisiansky  Island:  low,  oval  isle  of  coral  sand;  two  miles  by  three  miles;  lagoon 

empty  of  water;  surrounded  by  reef  which  extends  six  or  seven  miles  from  isle; 
vegetation  very  sparse. 

5.  Laysan  Island:  elevated,  oval  atoll;  two  miles  by  a mile  and  a half;  well-developed 

fringing  reef;  briny  lagoon;  abundant  scrubby  vegetation. 

6.  French  Frigates  Shoal:  crescentic  atoll,  with  numerous  low  sand  isles,  and  several 

high,  rocky  volcanic  isles;  area  of  shoal  about  30  square  miles;  extensive  reefs; 
grasses  and  low  vegetation  on  sand  isles. 

7.  Small  isles  along  the  coasts  of  Oahu,  most  of  them  formerly  connected  with  the 

island;  sparse  vegetation:  Kihewamoku,  Mokuaia;  Pulemoku;  Kukuihoolua; 
Mokualai;  Mokolii;  Kapapa;  Ahuolaka;  Kekepa;  Mokuoloe;  Mokolea 
Mokulua;  Kaonikaipu;  Mokauea;  Mokuoeo;  Onini;  Moku  Umaume;  Lau- 
launui. 

8.  Small  isles  along  the  coasts  of  Molokai,  most  of  them  formerly  connected  with 

the  island;  vegetation  sparse  or  absent:  Namoku;  Mokapu;  Okala;  Kuelo- 
Lepau;  Mokuhooniki;  Kanaha;  Puukole. 

9.  Small  isles  along  the  coasts  of  Hawaii:  Coconut  Island,  etc. 

Narrow  strands  are  characteristic  of  the  following  islands: 

10.  Niihau:  area  97  square  miles;  highest  point,  1,300  feet. 

11.  Kauai:  area  547  square  miles;  highest  point,  5,250  feet. 

12.  Oahu:  area  598  square  miles;  highest  point,  4,030  feet. 

13.  Molokai:  area  261  square  miles;  highest  point,  4,958  feet. 

14.  Maui:  area  728  square  miles;  highest  point,  10,032  feet. 

15.  Lanai:  area  139  square  miles;  highest  point,  3,400  feet. 

16.  Kahoolawe:  area  69  square  miles;  highest  point,  1,472  feet. 

17.  Hawaii:  area  4015  square  miles;  highest  point,  13,825  feet. 

A number  of  the  smaller  islands  of  the  Hawaiian  Archipelago 
rise  very  abruptly  from  the  sea,  and  are  characterized  by  steep  or 
precipitous  coasts.  The  following  are  of  this  type: 

18.  Gardiner  Island:  conical  rock,  700  feet  in  diameter,  175  feet  high;  cliffs  60-70 

feet  high  on  all  sides;  a smaller,  precipitous  rock  nearby. 

19.  French  Frigates  Shoal:  volcanic  rocky  islet  in  center  of  formerl  agoon;  180  feet 

long,  45  feet  wide,  120  feet  high;  vertical  walls;  barren. 

20.  Necker  Island:  remnant  of  volcanic  crater,  surrounded  by  reef;  isle  is  three 

quarters  of  a mile  long,  500  feet  wide,  and  300  feet  high;  scanty  vegetation 
sea-cliffs  on  all  sides. 


of  the  Hawaiian  Archipelago 


265 


21.  Nihoa,  Bird  Island  or  Moku  (Modu)  Manu:  volcanic  remnant;  three  quarters  of  a 

mile  long,  one  third  of  a mile  wide,  600-900  feet  high;  sea-cliffs  on  all  sides; 
vegetation  scanty. 

22.  Small  isles  along  the  coast  of  Niihau,  probably  at  one  time  connected  with  the 

island:  Kaula  and  Lehua,  small  eroded  cinder  cones  with  sea-cliffs  and  steep 
slopes. 

23.  Small  isles  along  the  coast  of  Oahu : Moku  Manu  (two  volcanic  remnants) ; Manana 

(Rabbit  Island),  eroded  crater,  with  sea-cliffs. 

24.  Small  isles  and  rocks  along  the  coasts  of  Molokai:  Mokolea,  Mokohola,  Moko- 

mana. 

25.  Small  isles  along  the  coasts  of  Maui:  Molokini,  etc. 

26.  Five  Needles:  a group  of  detached  pinnacle  rocks  about  120  feet  high,  situated 

five  and  a half  miles  north  of  Cape  Kaea,  Lanai,  and  about  the  middle  of  the 
bight  on  the  west  side  of  the  island. 

The  largest  strand  areas  on  any  single  island  occur  on  the 
island  of  Hawaii;  the  smallest  strands  are  those  of  the  tiny  islets 
in  the  westward  end  of  the  archipelago.  On  the  whole,  the 
Hawaiian  strand,  as  a phytogeographic  province,  is  poorly  de- 
veloped when  compared  with  the  Indo-Malayan  or  West  Indian 
strands,  or  with  those  of  numerous  other  archipelagoes. 

Subsidence  and  elevation 

A factor  of  far-reaching  importance  in  any  biological  studies  in 
the  Hawaiian  Archipelago  is  that  of  subsidence,  i.  e.,  the  islands 
are  but  the  apices  of  lofty  and  slowly-sinking  submarine  moun- 
tains. Physiographical  evidence  is  accumulating  to  show  that 
during  previous  stages  in  the  history  of  the  central  Pacific,  these 
islands  undoubtedly  stood  thousands  of  feet  higher  than  they  do  at 
present.  Many  stages  of  subsidence  and  erosion  may  be  found 
today  within  the  group,  ranging  from  the  large,  actively  volcanic 
island  of  Hawaii  (nearly  14,000  feet  in  elevation),  at  one  end  of 
the  chain,  to  the  tiny  coral  atolls,  but  a few  feet  above  sea-level, 
which  are  scattered  along  the  other  extremity. 

Considering  the  strand  zone  of  any  given  island,  it  is  evident 
that  through  a long  period  of  time  this  zone  has  been  slowly 
creeping  up  the  slopes  of  the  island,  and  the  terrestrial  vegetation 
has  been  crowded  into  steadily  diminishing  areas.  In  other  words, 
the  total  mileage  of  strand  was  formerly  much  greater  than  at 
present,  other  things  being  equal.  Granting  slow  subsidence  as 
the  prevalent  condition  of  Pacific  islands  (see,  in  this  connection,  an 
important  contribution  by  Bryan,  ’16),  the  great  strand  mileage 


266 


MacCaughey:  The  strand  flora 


of  an  island  like  Hawaii  steadily  decreases  until  ultimately  the 
condition  exhibited  by  the  tiny  strand  of  Laysan  or  Midway  is 
reached.  In  this  manner  the  subsidence-factor,  although  not  of 
especial  force  at  any  one  time,  has  been  through  long  periods  of 
time  a powerful  influence  on  the  strand  flora. 

Although  subsidence  has  been  the  dominant  note  in  Hawaii’s 
geological  history,  there  have  been  minor  elevations  within  recent 
times.  Raised  coral  reefs  and  beaches  occur  at  various  points 
along  the  coasts,  e.  g.,  along  the  southern  and  western  shores  of 
Oahu.  The  highest  reef  known  is  on  the  southwestern  end  of 
Mailiilii,  elevated  120  feet  above  the  sea.  Just  as  local  elevation 
at  such  points  as  Mokapu,  Kalihi,  and  the  Coral  Plain  has  pushed 
the  littoral  zone  seaward,  so  at  Hanalei,  Kahana,  Kaneohe,  and 
Pearl  Harbor  the  drowning  or  submergence  of  valley-mouths  has 
developed  deep  embayments,  and  the  littoral  flora  extends  deep 
into  the  lowland  zone  which  surrounds  it  on  three  sides.  It  is 
evident  that  sufficient  study  and  emphasis  has  not  been  given  to 
the  ecological  effects  of  these  gradual  changes  of  land-  and  sea- 
level. 

In  his  illuminating  studies  of  the  New  Zealand  flora,  Aston 
(’12)  concludes  that  the  raised  marine  beaches  at  Cape  Turakirae 
show  that  there  has  occurred  comparatively  recently,  and  perhaps 
within  historic  times,  rapid  elevation  of  the  coast  line.  Violent 
earthquakes  have  so  altered  the  physiography  of  the  littoral  as  to 
result  in  some  unusual  ecological  features. 

ORIGIN 

Relation  of  Pacific  Ocean  currents  to  the  dissemination 

OF  PLANTS  OF  THE  HAWAIIAN  LITTORAL 

The  importance  of  ocean  currents  as  agencies  for  the  distri- 
bution of  plants,  and  more  particularly  for  the  wide  dissemination 
of  beach  species,  has  long  been  recognized.  In  a vast  body  of 
water,  like  the  Pacific,  dotted  with  thousands  of  scattered  islands, 
the  surface  currents  assume  special  significance  in  relation  to  the 
migrations  of  plants,  animals,  and  man. 

The  surface  circulation  of  the  Pacific  is,  on  the  whole,  notably 
less  active  than  that  of  the  Atlantic.  The  vertices  of  the  rota- 
tional movements  are  marked  by  “Sargasso  Seas”  in  the  north  and 


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267 


south  basins,  but  these  quiet  areas  are  of  small  extent  when  com- 
pared with  the  well-known  Sargasso  Sea  of  the  North  Atlantic 
Ocean. 

Reference  should  here  be  made  to  the  Northern  Equatorial 
Current,  which  receives  important  contributions  from  the  great 
stream  that  sweeps  down  the  North  Pacific  coast  of  America. 
Many  of  the  largest  and  most  famous  of  the  Hawaiian  double 
canoes  were  hewn  from  Douglas  spruce  ( Pseudotsuga  taxifolia) 
which  had  been  carried  to  the  shores  of  Niihau,  Kauai,  and  other 
islands  by  the  currents.  It  is  a well-known  fact  that  the  natives 
of  the  Alaska  islands  obtain  much  of  their  fire-wood  as  drift 
from  the  Asiatic  coast.  Japanese  fishing-boats,  at  various  times 
in  history,  have  drifted  to  the  Hawaiian  Islands  and  to  the  north- 
west coast  of  America. 

Between  the  two  great  equatorial  currents  flowing  westward 
on  either  side  of  the  equator  there  is  a narrow  counter-equatorial 
current  flowing  to  the  east.  This  stream  is  largely  assisted  during 
the  latter  half  of  the  year  by  the  southwest  monsoon,  and  from 
July  to  October  the  southwest  winds  prevailing  east  of  150°  E. 
further  strengthen  the  current,  but  later  in  the  year  the  easterly 
winds  weaken  or  even  destroy  it.  The  currents  of  the  South 
Pacific  are  well  shown  in  Schimper’s  (’91)  monograph  of  the  Indo- 
Malayan  strand  flora. 

A feature  of  ocean  currents  as  seed  carriers  that  has  not  been 
sufficiently  emphasized  is  the  definiteness  of  their  courses.  This 
fact  is  well  illustrated  by  the  large  number  of  tree  trunks  and  logs 
from  the  North  Pacific  coast  that  are  annually  cast  upon  the 
Hawaiian  coasts.  These  trees  occur  in  a relatively  small  and  well- 
defined  region,  and  evidently  follow  a definite  course  across  the 
North  Pacific.  Wood-Jones  (T2)  performed  an  interesting  ex- 
periment to  determine  the  course  of  drift  material  in  the  Indian 
Ocean.  He  cast  adrift,  in  the  Cocos-Keeling  Islands,  bottles 
containing  messages.  One  was  picked  up  on  the  beach  of  Brava, 
Italian  Somaliland,  after  a journey  of  three  thousand  miles  across 
the  Indian  Ocean,  and  a second  one,  sent  out  nearly  a year  later, 
was  washed  ashore  at  precisely  the  same  place.  This  definiteness 
of  course  gives  to  the  ocean  currents  a high  potential  cumulative 
effect  as  carriers,  that  merits  more  than  passing  mention. 


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MacCaughey:  The  strand  flora 


Currents  in  the  vicinity  of  Hawaii 

The  United  States  Coast  Pilot  contains  data  concerning  the 
local  island  currents,  which  may  be  summarized  as  follows.  The 
strong  northeast  trades  begin  early  in  March,  blowing  well  from 
the  northward  until  May,  and  from  then  until  October  they  are 
more  easterly.  During  October  the  trades  are  light  with  frequent 
calms,  and  occasionally  a west  southwest  swell  sets  in.  During 
November  and  December  the  trades  are  strong  and  variable, 
occasionally  being  interruped  by  light  southerly  winds.  During 
January  and  February  southerly  and  southwesterly  gales  often 
prevail.  These  are  konas  and  are  from  a few  hours  to  two  or  three 
days  duration,  followed  by  rain. 

Hawaii. — Generally  the  currents  follow  the  trades  but  occa- 
sionally they  set  against  the  wind.  A current  follows  the  coast 
north  of  Cape  Kumukahi  around  Upolu  Point;  another  one  fol- 
lows the  trend  of  the  coast  offshore  southwestward  from  Cape 
Kumukahi  around  Kalae  and  northward  as  far  as  Upolu  Point. 
There  is  an  inshore  current  that  sets  southward  from  Okoe  Landing 
along  the  west  coast  around  Kalae,  and  thence  northeastward 
along  the  shore  as  far  as  Keauhou. 

Maui. — Generally  the  currents  set  with  the  trades.  A current 
follows  the  north  shore  of  Maui  westward  from  Kauiki  Head  and 
draws  down  through  Pailolo  Channel;  the  current  is  stronger  on 
the  Molokai  side  of  the  channel.  A strong  current  follows  the 
coast  southward  of  Kauiki  Head  until  past  Kahoolawe.  In  the 
vicinity  of  Lahaina  the  current  generally  sets  northwestward. 

Molokai. — The  current  sets  westward  along  the  entire  north- 
erly coast,  and  about  half  the  length  of  the  southerly  shore,  where 
an  easterly  current  prevails. 

Oahu. — The  currents  around  Oahu  are  variable  in  strength 
and  direction,  but  the  general  movement  of  the  water  along  the 
coast  is  westward  or  northwestward,  the  direction  being  modified 
by  the  trend  of  the  coast. 

Kauai. — Currents  are  very  uncertain  as  to  direction  but  they 
generally  follow  the  winds,  though  frequently  setting  in  the  oppo- 
site direction  during  the  first  calms  after  strong  trades. 

A careful  study  of  any  good  map  which  depicts  the  ocean  cur- 


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269 


rents  of  the  North  Pacific  Ocean  will  graphically  show  that  the 
Hawaiian  Archipelago  is  practically  outside  the  zone  of  influence 
of  the  great  currents  that  would  naturally  bring  the  seeds  of 
tropical  plants  to  her  shores.  Guppy’s  statements  (’06,  pp.  75,  64) 
are  pertinent  in  this  connection: 

The  currents  of  the  Pacific  have  failed  to  establish  the  numerous  beach-trees 
(possessing  buoyant  fruits)  of  the  Pacific  Islands,  not  only  in  the  Hawaiian  group, 
but  also  on  the  coast  of  America;  and  it  is  therefore  argued  that  we  should  expect  the 
Hawaiian  group  to  have  received  through  the  currents  its  shore-plants  with  buoyant 
seeds  or  fruits  from  the  tropical  west  coasts  of  America. 

In  support  of  this  contention  it  is  pointed  out  that  most  of  the  Hawaiian  strand- 
plants  that  are  dispersed  by  the  currents  are  found  in  America,  and  some  indeed  in 
America  to  the  exclusion  of  the  Old  World. 

The  arrangement  of  the  currents  in  the  North  Pacific  also  favours  the  view  that 
the  Hawaiian  Islands  are  more  likely  to  receive  plants  by  the  agency  of  the  currents 
from  America  than  from  the  Asiatic  side  of  the  Pacific. 


Speaking  generally  of  the  extension  eastward  of  the  Indo-Malayan  strand-plants 
over  the  Pacific,  Professor  Schimper  ([’91]  page  195)  remarks  that  they  become  fewer 
and  fewer  in  number  as  they  extend  farther  from  their  original  home,  their  number 
shrinking  to  a very  few  in  the  most  remote  groups  of  the  Marquesas  and  the  Hawaiian 
Islands.  . . . The  number  actually  introduced  through  the  currents  into  Hawaii  in 
all  likelihood,  therefore,  does  not  exceed  ten. 

Importance  of  drift  material 

Drift  material  is  much  more  abundant  along  the  Hawaiian 
windward  shores  than  on  the  leeward  shores.  Nowhere  does  it 
attain  the  proportions  that  characterize  many  other  regions  else- 
where on  the  globe.  Certain  districts,  for  example,  the  south- 
east coast  of  Hawaii,  between  Honuapo  and  Kalae,  particularly 
the  Kamilo  beach  near  Kaluwalu,  seem  to  be  much  more  favor- 
ably situated  for  the  reception  and  accumulation  of  drift  than  do 
others. 

Tansley  and  Fritsch  (’05)  describe  the  abundant  drift  on 
portions  of  the  Ceylon  littoral,  and  note  the  great  variety  of  plant 
fragments,  fruits,  and  seeds: 

The  thickest  masses  of  drift  were  very  moist  and  quite  warm  to  the  hand,  and 
in  this  natural  forcing  bed  many  different  plants  had  germinated.  The  thick  line  of 
brown-black  humus  with  the  fresh  green  leaves  of  the  seedlings  arising  from  it  at 
intervals  was  a most  striking  sight.  Of  these  the  most  conspicuous  were  Cerbera 
odollam,  Calophyllum  inophyllum,  Bruguiera  gymnorhiza,  Crinum  asiaticum,  and 
Colocasia  antiquorum  (from  bits  of  old  rhizome). 

Moseley  (’79,  p.  367)  reports  from  the  Moluccas  living  epiphytic 


270 


MacCaughey:  The  strand  flora 


orchids  and  young  palms  as  part  of  the  drift,  washed  high  up  on 
the  beach  and  growing.  He  states: 

We  passed  large  quantities  of  leaves,  fruits,  and  flowers,  and  branches  of  trees 
floated  off  from  the  shores.  ...  I was  astonished  at  the  large  quantities  of  fresh  vege- 
table matter  thus  seen  floating  on  the  sea.  ...  Not  only  are  large  quantities  of 
fruits  [containing  seeds]  capable  of  germinating  thus  transported  from  island  to 
island,  but  entire  living  plants,  even  trees,  are  washed  from  island  to  island  and 
transplanted  by  the  waves. 

Hooker  (’47,  p.  253)  states  that  the  majority  of  the  littoral  species 
of  the  Galapagos  Islands  have  reached  the  islands  through  oceanic 
and  aerial  currents.  There  are  about  twenty  such  plants,  mostly 
species  common  to  warm  latitudes.  Some  of  these  are:  Cissam- 
pelos  Pariera,  Tribulus  cistoides,  Tephrosia  littoralis,  Verbena 
littoralis,  Avicennia  tomentosa , Scaevola  Plumieri , Ipomoea  mari- 
tima,  Calystegia  Soldanella,  and  Heliotr opium  curas savicum. 
Hooker  attributes  the  following  plants  of  the  Peruvian  and  Chilean 
littoral,  which  occur  on  the  Galapagos  strand,  to  ocean  currents: 
Vigna  oahuensis,  Acacia  Cavenia , Nicotiana  glutinosa,  Dictyocalyx 
Miersii,  Ly coper sicum  peruvianum,  Verbena  littoralis,  V.  polystacha, 
and  Plantago  tomentosa. 

Flotation  adaptations  of  strand  plant  seeds 

In  his  monograph  on  the  Indo-Malayan  strand  flora  Schimper 
(’91,  pp.  163-178)  makes  the  following  classification  of  strand 
plants,  based  upon  the  flotation  characters: 

1.  Driftfriichte  und  Driftsamen  mit  grossen  luftfiihrenden  Hohlraumen.  Examples: 

fruits  of  Heritiera  littoralis,  Thespesia  populnea,  Pongamia  glabra,  and 
Derris  uliginosa;  seeds  of  Mucuna  species,  Caesalpinia  Bonducella,  Vigna 
lutea.  Hibiscus  tiliaceus,  Dodonea  viscosa,  Euphorbia  Atoto,  Suriana 
maritima,  Ipomoea  pes  caprae,  Pangium  edule  (?),  Colubrina  asiatica  (?), 
Morinda  citrifolia. 

2.  Driftsamen  mit  schwammigen  Samenkern.  Examples:  many  Leguminosae,  such 

as  Sophora  tomentosa  and  species  of  Erythrina  and  Canavalia;  embryos  of 
Rhizophora  and  Avicennia. 

3.  Driftfriichte  und  Driftsamen,  deren  Schwimmfahigkeit  durch  luftfiihrendes 

Schalengewebe  bedingt  ist. 

A.  Schwimmgewebe  peripherisch.  Examples:  Clerodendron  inerme,  Carapa 
species,  Cordia  subcordata,  Wollastonia  glabra,  Tournefortia  argentea, 
Pemphis  acidula. 

a.  Schwimmgewebe  mit  grossen  Intercellularraumen.  Examples:  Cerbera 
Odollam,  Laguncularia  racemosa,  Nipa  fruticans. 

b.  Schwimmgewege  ohne  oder  nur  mit  winzigen  Intercellularraumen.  Ex- 
amples: fruits  of  Cocos  nucifera,  Barringtonia  speciosa,  B.  excelsa,  Ter - 


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271 


minalia  Katappa,  Conocarpus  erecta,  Lumnitzera  racemosa , L.  coccinea, 
Scyphiphora  hydrophyllacea,  Guettarda  speciosa,  Tournefortia  argentea, 
Wollastonia  \glabra,  Scaevola  Koenigii,  Clerodendron  inerme , Cynometra 
cauliflora,  Cordia  subcordata;  seeds  of  Carapa  moluccensis,  C.  obovata, 
Sonneratia  species,  Pemphis  acidula. 

B.  Das  Schwimmgewebe  befindet  sich  innerhalb  einer  harten  Stein-  oder  Samen- 
schale.  Examples : fruits  of  Calophyllum  inophyllum  and  Ximemia  ameri- 
cana;  seeds  of  Cyas  circinalis  and  Excoecaria  Agallocha. 

Guppy  (’06,  p.  531)  enumerates  the  following  seeds  or  seed 
vessels  that  remained  afloat  after  a year’s  flotation  in  sea-water: 
Thespesia  populnea , Mucuna  gigantea , Dioclea  sp.,  Strongylodon 
lucidum,  Sophora  tomentosa,  Caesalpina  Bonducella,  Entada  scan - 
dens , Morinda  citrifolia , Scaevola  Koenigii , Cordia  subcordata , 
Tournefortia  argentea , Ipomoea  grandiflora,  and  Tacca  pinnatifida. 

In  Helmsley’s  classification  of  the  Bermudian  flowering  plants 
(’85,  p.  48)  the  following  indigenous  genera,  chiefly  littoral  forms, 
are  listed  as  having  probably  been  conveyed  to  the  island  by  ocean 
currents:  Cakile,  Hibiscus,  Suriana , Elaeodendron,  Sapindus, 

Dodonaea,  Cardiospermum , Rhus,  Sophora,  Vigna,  Canavalia, 
Centrosema,  Conocarpus,  Rhizophora,  Opuntia,  Sesuvium,  Rhachi- 
callis,  Chiococca,  Morinda,  Solidago,  Borrichia,  Scaevola,  Tourne- 
fortia, Heliotropium,  Ipomoea,  Convolvulus , Avicennia,  Coccoloba, 
Atriplex,  Salicornia,  Euphorbia,  Croton,  Ruppia,  Zostera,  Cenchrus, 
Spartina,  Stenotaphrum,  Sporobolus,  Chloris. 

Helmsley  (’84,  p.  304)  has  also  recorded  the  actual  germination 
of  various  drifted  seeds  after  being  cast  ashore.  He  lists  Hibiscus 
tiliaceus,  Vitis  vinifera,  Sapindus  Saponaria,Anacardiumoccidentale, 
Aleurites  moluccana,  Ricinus  communis,  Cocos  nucifera,  and  Sagus 
sp.  Of  Vitis  vinifera  he  records  the  foundering  of  a vessel  laden 
with  a cargo  of  white  Lisbon  grapes,  off  the  south  shore  of  Bermuda. 
Many  of  the  grapes  were  washed  ashore,  and  the  seeds  germinated 
at  high-water  mark.  Numbers  of  plants  were  taken  up,  out  of 
curiosity,  and  transplanted,  and  bore  fruit.  Martins  raised  plants 
from  seeds  of  Ricinus  communis  that  had  been  floating  for  ninety- 
three  days  upon  the  surface  of  the  sea. 

Shull’s  (’14)  extensive  experiments  show  that  the  seeds  of 
many  species  will  germinate  after  four  years  of  continuous  sub- 
mergence in  fresh  water,  and  that  the  seeds  of  three  species  were 
viable  after  seven  years  of  continuous  submergence. 


272 


MacCaughey:  The  strand  flora 


Guppy  (’06,  p.  529)  shows  that  of  the  littoral  plants  of  Fiji  and 
Tahiti,  75-80  per  cent,  have  seeds  or  fruits  that  will  float  un- 
harmed for  two  months  or  more,  and  that  about  30  per  cent,  of 
this  number  are  legumes.  He  says: 

In  the  course  of  the  ages  the  plants  with  buoyant  seeds  or  seed  vessels  have  been 
gathered  at  the  coast.  This  is  indicated:  (1)  By  the  far 'greater  proportion  of  species 
with  buoyant  seeds  and  seed  vessels  amongst  the  shore  plants  than  among  the  inland 
plants.  (2)  By  the  circumstance  that  almost  all  the  seeds  or  seed  vessels  that  float 
unharmed  for  long  periods  belong  to  shore  plants.  (3)  By  the  fact  that  when  a genus 
has  both  inland  and  littoral  species,  the  seeds  or  fruits  of  the  coast  species  as  a rule 
float  for  a long  time,  while  those  of  the  inland  species  either  sink  at  once  or  float  only 
for  a short  period. 

Guppy  (’06,  p.563)  makes  the  following  list  of  “ Hawaiian 
plants  with  buoyant  seeds  and  fruits  known  to  be  dispersed  by  the 
currents  either  exclusively  or,  as  in  a few  species,  with  the  assistance 
of  frugivorous  birds”:  Colubrina  asiatica,  Dioclea  violacea , 
Mucuna  gigantea,  M.  mens , Strongylodon  lucidum , Vigna  lutea , 
Caesalpinia  Bonducella,  Scaevola  Koenigii,  Ipomoea  glaberrima, 
I.  Pes-caprae,  Vitex  trifolia  and  Cassytha  fdiformis.  Although 
many  strand  plants  possess  seeds  or  fruits  that  can  float  for  long 
periods,  other  widely  distributed  species  possess  feeble  or  no  flota- 
tion power.  It  is  necessary  to  recognize  other  agencies. 

Trees  and  logs  as  disseminators 

Logs  and  tree-trunks  of  various  coniferous  species  from  the 
Puget  Sound  region  are  commonly  cast  ashore  upon  the  Hawaiian 
windward  coasts.  It  is  a matter  of  common  observation  that  on 
all  windy  coasts,  small  seeds,  like  sand,  are  blown  into  every 
available  cranny.  In  this  way  many  lodge  in  the  holes  and  cracks 
in  drift-wood,  which  is  floated  off  at  high  tide  or  during  storm  time, 
and  thus  the  seeds  or  fruits  may  be  carried  to  new  localities. 
Strand  seeds  or  fruits  which  do  not  possess  special  flotation  devices 
may  be  carried  to  new  shores.  Moreover,  the  seeds  of  inland 
species  may  be  carried  by  trees  which  have  been  uprooted  by 
inundations  or  storms,  either  in  the  soil  around  the  roots,  or  in  the 
bark,  etc. 

Ernst  (’08,  p.  56)  states  that  “ tree  stems  and  branches  played 
an  important  part  in  the  colonization  of  Krakatau  by  plants 
and  animals.”  Hedley  (T5)  records  a log  of  Dammara  australis 


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273 


the  New  Zealand  Kauri,  as  stranding  on  the  windward  reef  of 
Funafuti.  Wood-Jones  (’05)  gives  an  excellent  account  of 
tree-trunks  and  “floating  islands”  of  storm -washed  vegetation 
as  carriers  of  seeds,  animals,  etc.,  to  the  Cocos-Keeling  group. 
He  emphasizes  the  importance  of  trees  with  buttressed  bases  as 
disseminators : 

These  buttresses  are  in  the  form  of  large  thin  wings,  which  taper  to  the  trunk 
above,  and  below  form  a series  of  compartments  like  stalls  in  a circular  stable.  With- 
in these  stalls  much  earth  is  held  fast  by  the  interlacing  of  smaller  roots,  and  when 
such  a tree  is  uprooted,  and  set  adrift  to  sea,  it  carries  its  earth  with  it.  It  may  carry 
it  for  very  great  distances,  and  I have  seen  a buttressed  tree  come  ashore  in  the  atoll, 
from  whose  base  a wheelbarrow-load  of  fine  red  earth  might  have  been  collected. 

Floating  rocks  as  disseminators 

The  idea  of  floating  rocks  as  disseminators  of  littoral  plants 
might  be  met  with  incredulity,  were  it  not  for  the  testimony  of 
many  reliable  observers.  Among  the  volcanic  islands  of  the  East 
Indies  large  blocks  of  pumice  float  for  many  weeks,  and  are  carried 
many  hundred  miles  from  their  points  of  origin.  The  salient 
points — prolonged  flotation  of  the  blocks;  presence  of  numerous 
kinds  of  seeds  in  the  crevices  and  pores  of  the  pumice;  and  the 
germination  of  these  seeds  when  the  block  is  cast  upon  a favorable 
beach-situation — have  all  been  corroborated  by  careful  investi- 
gators. Ernst  (’08,  p.  56)  states  that  floating  blocks  of  pumice  con- 
stitute an  important  dispersal  agency  in  the  Sunda-S traits  region. 

Although  there  is  very  little  pumice  to  be  found  on  the  Ha- 
waiian coasts  at  the  present  time,  there  is  abundant  evidence  that 
in  earlier  periods  in  the  geologic  history  of  the  islands,  repeated 
volcanic  explosions,  resulting  in  pumice  production,  have  taken 
place.  There  are  today  extensive  pumice  beds  around  the  vol- 
cano Kilauea.  Therefore,  although  pumice  blocks  play  little  or 
no  part  in  the  dispersal  of  plants  in  the  Hawaiian  group  at  present, 
it  is  entirely  possible  that  they  had  a more  important  role  in 
earlier  times,  at  least  in  distributing  seed  from  island  to  island. 

Floating  masses  of  dead  coral  may  also  be  ranked  as  possible 
seed-carriers.  Wood-Jones  (’15)  found  numerous  instances  of 
this  in  the  Cocos-Keeling  group.  The  innumerable  air-cavities 
in  certain  kinds  of  coral  render  it  buoyant.  The  block  is  cast 
upon  a beach  at  storm  time;  it  lies  there  for  an  indefinite  period; 


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earth,  sand,  and  seeds  lodge  in  its  many  crevices;  another  storm 
sets  it  again  adrift ; and  it  may  be  cast  ashore  upon  a distant  strand . 
Coral  blocks  of  this  sort  are  infrequent  on  Hawaiian  shores,  owing 
to  the  relative  paucity  of  fringing  reef,  and  have  probably  been  of 
minor  significance  in  seed  dispersal.  They  constitute,  however, 
a possible  factor,  particularly  on  Oahu,  Kauai,  and  the  leeward 
isles. 

COMPOSITION— A CLASSIFIED  LIST  OF  THE 
HAWAIIAN  STRAND  PLANTS 

I.  True  littorals 

Species  which  occur  only  or  chiefly  within  the  strand  zone. 

Endemic  littorals 
Trees  and  shrubs 

There  are  no  endemic  trees  that  are  strictly  littoral.  This  is  a 
significant  feature  of  the  Hawaiian  flora.  The  shrubs  are: 

Lycium  sandwicense  Gray  Scaevola  coriacea  Nutt. 

N ototrichium  humile  Hillebd.  Solarium  Nelsoni  Dun. 

Santalum  Freycinetianum  Gaud.  S.  laysanense  Bitter 

var.  littorale  Hillebd.  Wikstroemia  Uva-ursi  Gray 

Phyllostegia  variabilis  Bitter 

Herbaceous  plants 

Achyranthus  splendens  Mart.  Lipochaeta  connata  (Gaud.)  DC. 
A.  splendens  var.  rotundata  Hil-  var.  littoralis  Hillebd. 

lebd.  L.  integrifolia  (Nutt.)  Gray 

Campylotheca  molokaiensis  Hil-  L.  succulenta  (Hook.  & Arn.)  DC. 

lebd.  Schiedea  globosa  Mann 

Fimbristylis  pycnocephala  Hil-  S'.  Lydgatei  Hillebd. 

lebd.  Sporobolus  virginicus  (L.)  Kunth 

Kadua  littoralis  Hillebd.  var.  phleoides  Hillebd. 

Lepidium  owaihense  Cham.  & Tetramolopium  sp. 

Schlecht. 

2.  Indigenous  littorals 
Trees  and  shrubs 

There  are  no  indigenous  trees  that  are  strictly  littoral.  Shrubs : 
Colubrina  asiatica  (L.)  Brongn.  Gossypium  tomentosum  Nutt. 


of  the  Hawaiian  Archipelago 


275 


Heliotr opium  anomalum  Hook.  Sesbania  tomentosa  Hook.  & Arn. 

& Arn.  Vitex  trifolia  L. 

Scaevola  Lobelia  Murr. 

Herbaceous  plants 


Argyreia  tiliaefolia  ( Desr  ) Wight 
Boerhaavia  diffusa  L. 

Cressa  cretica  L. 

Cyperus  laevigatus  L. 

Euphorbia  cor  data  Meyen 
Heliotr  opium  curassavicum  L. 
Herpestis  Monnieria  H.  B.  K. 
Ipomoea  acetosaefolia  (Vahl) 
Roem.  & Schl. 

/.  glaberrima  Bojer 
I.  insularis  Steud. 


Ipomoea  Pes-caprae  (L.)  Sweet 
Lepturus  repens  R.  Br. 
Lysimachia  spathulata  Benth.  & 
Hook. 

Ruppia  maritima  L. 

Scirpus  maritimus  L. 

Sesuvium  F ortulacastrum  L. 
Sporobolus  virginicus  (L.)  Kunth 
Tephrosia  piscatoria  (Soland.) 
Pers. 


3.  Littorals  introduced  by  the  primitive  Hawaiians* 

Trees 

Calophyllum  Inophyllum  L.  Cordia  subcordata  Lam. 

Cocos  nucifera  L. 

4.  Littorals  introduced  since  the  advent  of  Europeans 

(1555-1778  TO  DATE) 

Trees  and  shrubs 

No  true  littoral  trees  and  shrubs  have  been  introduced. 
Herbaceous  plants 

Batis  maritima  L.  Polypogon  littoralis  (With.)  Sm. 

II.  Pseudo-Littorals 

Species  which  chiefly  inhabit  the  lowlands  or  other  zones,  and 
which  appear  on  the  strands  in  the  role  of  invaders  from  the  interior. 

1.  Endemic  pseudo-littorals 
Trees  and  shrubs 

Acacia  koa  Gray  Erythrina  monosperma  Gaud. 

Cassia  Gaudichaudii  Hook  & Myoporum  sandwicense  (A.  DC.) 

Arn.  Gray 

Chenopodium  sandwicheumMoq. 


* Thespesia  populnea  Soland.  should  be  noted  here. 


276 


MacCaughey:  The  strand  flora 


Herbaceous  plants 

Car  ex  sandwicensis  Boeckl.  Peucedanum  sandwicense  Hillebd. 
Jacquemontia  sandwicensis  Gray  Sicyos  hispidus  Hillebd. 

Nama  sandwicensis  Gray  5.  micro  car  pus  Mann 


2 Indigenous  pseudo-littorals 
Trees  and  shrubs 

Caesalpinia  Bonducella  (L.)  Pritchardia  spp. 

Flem.  Tribulus  cistoides  L. 

Metrosideros  polymorpha  Gaud. 


Herbaceous  plants 


Argemone  mexicana  L. 

Cassytha  filiformis  L. 

Cenchrus  calyculatus  (^preng.) 
Cav. 

Chenopodium  album  L. 

Cladium  leptostachyum  Nees 
Cyperus  pennatus  Lam. 

C.  phleoides  Nees 
Eragrostis  hawaiiensis  Hillebd. 
Erythraea  sabaeoides  (Griseb.) 
Gray 


Fleurya  inter rupta  Gaud. 
Kyllingia  monocephala  Rottb. 
Lythrum  maritimum  H.  B. 
K. 

Malvastrum  tricuspidatum  (Ait.) 
Gray 

Mucuna  gigantea  (Willd.)  DG. 
Ophioglossum  vulgatum  L. 

Sida  spp. 

Vigna  lutea  (Sw.)  Gray 
Waltheria  americana  L. 


3 Pseudo-littorals  introduced  by  primitive  Hawaiians 

Trees 

Aleurites  moluccana  (L.)  Willd.  Morinda  citrifolia  L. 

Hibiscus  tiliaceus  L.  Pandanus  odoratissimus  L.  f. 

4.  Pseudo-littorals  introdu  ed  since  the  advent  of 

Europeans 

Trees  and  shrubs 

Acacia  farnesiana  Willd.  Leucaena  glauca  (Willd.)  Benth. 

Casuarina  equisetifolia  Stickman  Prosopis  juliflora  (Sw.)  DC. 
Hibiscus  Rosa- sinensis  L. 


of  the  Hawaiian  Archipelago 


277 


Herbaceous  plants 


Abrus  precatorius  L. 
Achyranthus  aspera  L. 
Cardiospermum  Halicacabum  L. 
Crotalaria  spp. 

Cynodon  Dactylon  (L.)  Pers. 
Cyperus  umbellatus  Vahl 
Datura  Stramonium  L. 
Euphorbia  pilulifera  L. 


Euxolus  viridis  Moq. 

Hydrocotyle  verticillata  Thunb. 
Indigofer  a Anil  L. 
Mesembryanthemum  spp. 
Portulaca  oleracea  L. 

Salvia  occidentals  Sw. 

Samanea  Saman  (Benth.)  Merrill 
Xanthium  echinatum  Murr. 


There  are  numerous  ruderals,  in  addition  to  those  indicated 
in  the  last  section,  that  occur  at  random  on  the  various  beaches. 
College  of  Hawaii,  Honolulu 


